Fubnace



A. J. IVICGEHEE.

FURNACE.

APPLlcATxoN FILED 1ULY 5.1918.

Patented 0st. 2]., 1919.

UNITED STATES BNER JUDSON MGGEHEE, 0F JACKSON, TENNESSEE.

FURNACE.

miams.

Specification of Letters Patent.

Application led July 5, 1918. Serial No. 243,405.

To all whom t may concern:

Be it known that 1, ABNER d. MCGEHEE, a citizen of the United States, and a resident of Jackson, in the county of Madison and State ofl Tennessee, have invented certain new and useful Improvements in Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in furnaces and more particularly to a system for returningsmoke and gases to the ire chamber,-one object of the invention being to provide simple and efficient means to effeet economy in the use of fuel; to insure efficient combustion of returning gases mixed with air; to pijovide a construction in which fresh air will be preheated by heat supplied by the furnace before said air is mixed with the gaseous products of combustion from the furnace, and to insure proper and eilicient circulation of the mixed air and gases.

With these and other objects in View, the invention consists in certain novel features of construction and combinations of parts as hereinafter set forth and pointed out in the claims.

In the accompanying drawings; Figure-1 is a view partly in section showing an embodiment of my invention, and Figs. 2 and 3 are views of modifications.

1, 2 represent two steam |boiler furnaces constituting a battery, but it will be understood that my improvements are applicable to a battery comprising a greater number of furnaces.

A flue 3i is located horizontally over the plurality of furnaces and communicates with the smoke box of each of them,-one end of said ue being closed and the other end communicating wlth a stack 4f, which latter may be located entirely outside of the furnace house, and dampers 4a are located where said Hue communicates with the smoke boxes of the furnaces.

The horizontal flue is divided by a partition 5 into chambers 6, 7 ,-the lower of which communicates with the smoke boxes of the furnace. The upper Hue chamber 7 constitutes a mixing chamber and its end near the stack is adapted to be closed by a damper 8. The lower chamber 6 is adapted to communicate with the mixing chamber 7 through openings 9, 10 (of appreciably less width than that of the partition) controlled by dampers 11, 12.

A. return pipe 11a is connected with the mixing chamber near its forward' end (which is normally closed by the damper 8) and said pipe 11, after extending rearwardly and downwardly, communicates with the two furnaces under the grates thereof,- said return pipe being made with two branches 11b, 11c for this purpose. Each branch of the return pipe may be provided with a damper 17 and lateral pipes 18 project from the respective branches of the return pipe and are provided with nozzles 19 which enter the fire chamber,said nozzles being adapted to discharge rearwardlyand prevent the fiame from'playing constantly against any one part of the boilers.

A fresh air pipe 12a passes transversely through the flue chamber 6 and communi- Cates with the mixing chamber 7 in such manner that the draft of products of combustion passing through said chamber will tend to draw air into said chamber.

rlhe fresh air pipe extends downwardly in close proximity to one of the furnaces and its boiler so that the air passing through said pipe will be preheated before'it enters the mixing chamber. A damper 13 is located in the air pipe and in proximity to this damper, a fan 14 is adapted to force the air into the air pipe, said damper being so located that it may be operated to control the force of air forced into the pipe by-the 1t will be seen that with my improvements, the air will enter the mixing chamber in a preheated .condition and it will be kept hot while in said chamber, and the hot air mixed with the products of combustion from the furnace will .be caused to flow through the return pipe to the fire boxes of the furnaces, where ready and eiicient combustion of the mixed hot air and gases will be caused.

When the furnaces are rst fired, the damper 8 may be opened to increase the draft through the stack and when only one of the furnaces is fired at a time, one of the dempers 11 or 12 andthe damper 4 of the idle furnace may be closed.

ln the construction shown in Fig. 2, the mixing chamber 7 is formed within the smoke Hue 3 by meansof a ipe or tube 15 located centrally within the latterf-the portion of said flue 3 surrounding the tube Patented oet. 21, 1919.. i

15 forming the Hue chamber 6,-and the outer end of said tube near the stack is provided with a damper 16.

In the form of the invention shown in Fig. 3, the mixing chamber is formed by a tubular extension 20 disposed upon and at right angles to the Hue 3,-said tubular extension communicating at its lower end with the Hue 3 where the entrance of products of combustion is controlled by a damper 21. The upper end of the tube 20 is closed and the return pipe 1la is connected with said tube near its closed upper end. An air inlet pipe 22 communicates with the tube 20 near the lower end of the latter and is located near the smoke Hue and the adjacent boiler andis controlled by a damper 23. A fan 24 is provided to force air through the fresh air pipe 22.

Other changes might be made in the details of construction of my invention without .departing from the spirit thereof or limitin its scope and hence I do not wish to restrict myself to the precise details herein set forth.

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is z- '1. The combination with a furnace and its stack, of a horizontal Hue located over the furnace and communicating with the same and with the stack, a mixing chamber associated and communicating with said horizontal Hue, a damper for controlling such communication, an air inlet for the mixing chamber located to supply air heated by the furnace to the mixing chamber, and a return pipe communicating withy the mixing chamber and with the furnace.

2. The combination with a plurality of furnaces and a stack, of a horizontal smoke Hue located over said furnaces and communicating therewith and with the stack, a mixing chamber located within said horizontal Hue and adapted to communicate therewith and with the stack, dampers for controlling such communication, an air inlet located to admitl heated air to the mixing chamber, a return pipe connected with said mixing chamber and with the furnaces, and means'for forcing a draft through said mixing chamber and return pipe. p

3. The combina ion with a battery of furnaces and a stack, ofl a horizontal smoke Hue located over the furnaces and communicating therewith and with the stack, a mixing chamber within said Hue and adapted to communicate therewith and with the stack, dampers for controlling such communication, an air pipe entering the horizontal Hue and communicating with the mixin chamber therein, said pipe being located in position to be heated by furnace heat, a return pipe communicating with the mixing chamber and with the furnaces, and a fan located to create a draft through the air pipe, mixing chamber and return pipe.

4. The combination with a plurality of furnaces having smoke boxes, and a stack,

fof a horizontal Hue located over the furnaces, a partition dividing said Hue into two chambers, one of which communicates with the smoke boxes of the furnaces, and the other of said chambers constituting a mixing chamber adapted to communicate with the Hrst-mentioned chamber and with the stackq dampers for controlling such communication, a return Hue communicating with the end portion of the mixing chamber near the stack and with the furnaces, an air pipe communicating with the other end of the mixing chamber in position to admit air heated by the furnace, and means for forcing a draft through the mixing chamber and return pipe.

In testimony whereof, I have signed this specification in the presence oftwo subscribing witnesses.

ABNER JUDSON MCGEHEE,

Witnesses:

T. B. CARROLL, CARL F. WARD. 

